Mercury switch



Aug. 3,1965 R. TETTKE, sR., ETAL 3,198,919

MERCURY SWITCH Filed Aug. 1, 1962 mvsmons ROMAN TE 7'7'KE, SR WILL/AM U HE NR/C H United States Patent $198919 MERCURY SWITCH Roman Tettise, Sr., Rutherford, and William J. Heinrich,

edar Grove, NJ assignors to The Bendix Corporation, Teterhoro, N.J., a corporation of Delaware Filed Aug. 1, 1962, Ser. No. 214,026 3 Claims. (Cl. Ell-152) This invention relates to an improved gravity operated mercury switch and more particularly to such a mercury switch which is sensitive only to tilt along its lateral axis and is independent of the tilt position of the switch along the longitudinal axis thereof.

An object of the invention is to provide a mercury switch which may be used in a gyroscopic device for detecting changes in position of an aircraft while being immune to any variations in roll of the aircraft and which type of mercury switch may also be adapted for use in connection with a gyroscopic device for detecting roll of the aircraft while being immune to variations in the pitch of the aircraft.

Another object of the invention is to provide an improved switch structure which is particularly adapted for use in a mercury switch and which includes the feature of a common electrode with which a globule of mercury makes continuous contact and the further provision of a pair of novel semi-circular or U-shaped make or break contact elements arranged in spaced relation to the common electrode.

Another object of the invention is to provide in such a switch structure an arrangement in which upon the tilt of the switch about its lateral axis, the globule of mercury may selectively make a connection between the common electrode and one of the U-shaped elements.

Another object of the invention is to provide the U- shaped contact elements in an arrangement essentially coaxially about the longitudinal aXiS of the switch so that irrespective of the rotation of the switch about the longitudinal axis, the globule of mercury may remain in contact with the selected U-shaped element so long as the switch remains in the tilted relation even though the rotational aspect of the switch about the longitudinal axis thereof may change.

In providing the present novel structural arrangement of the present invention, the inventors thereof have heretofore experimented with the provision of completely circular contact elements in place of the U-shaped contact elements to solve the problem presented. However, because of the difliculty encountered in the globule of mercury tending to collect in two or more separate droplets at either side of such circular contact elements, this structure was discarded in favor of the discovery that the semi-circular open or U-shaped contact elements herein described successfully eliminated this ditliculty.

These and other objects and features of the invention are pointed out in the following description in terms of the embodiment thereof which is shown in the accompanying drawing. It is to be understood, however, that the drawing is for the purpose of illustration only and is not a definition of the limits of the invention, reference being had to the appended claims for this purpose.

The drawing is a perspective view of a novel mercury switch embodying the invention and in which the switch envelope has been broken away so as to better illustrate the co-operating switch structure therein.

Referring to the drawing, there is indicated by the numeral an elongated tubular envelope of glass or other suitable material having a longitudinal axis XX and a lateral axis Y-Y. The axis YY extends transverse to the longitudinal axis XX and intermediate the opposite ends of the tubular envelope 10.

Fused in one end of the tubular envelope is a common ddddfild Patented Aug. 3, 165

electrode 12 which extends longitudinally in the envelope It) in parallel relation to the longitudinal axis XX. A second electrode 14 is fused in the aforenoted end of the tubular envelope 10 and extends from this end of the envelope 10 in parallel relation to the longitudinal axis XX and in spaced relation to the common electrode 12.

Extending through the opposite end wall of the envelope 10 is a third electrode 16 also arranged in parallel arrangement to the longitudinal axis XX and in spaced relation to the common electrode 12. Inner ends of the electrodes 14 and 16 are positioned within the envelope 1% in spaced relation one to the other.

Mounted on the inner end of the electrode 14 is a novel U-shaped make or break contact member 18. There is further mounted on the inner end of the electrode 16 a similar novel U-shaped make or break contact member 29.

There is further provided a globule of mercury 22 in continuous contacting relation with the common electrode 12 normally arranged so as to be out of contacting relation with the electrode 14 and the electrode 16 upon the envelope 19 being in a level position.

However, upon the envelope 1% being tilted about the lateral axis YY extending perpendicular to the longitudinal axis XX, the globule of mercury 22 will establish an electrical contact between the common electrode 12 and the novel U-shaped contact element 18 or between the common electrode 12 and the novel U-shaped contact element 20 dependent upon the sense of the tilt about the lateral axis YY. This contacting relation will remain even though the switch envelope 1% be rotated about the longitudinal axis XX.

In the aforenoted arrangement, the electrodes 12, 14, and 16 are arranged about the longitudinal axis XX so that irrespective of the rotation of the switch envelope 10' about this axis XX, the globule of mercury 22 remains in contact with the same pair of electrodes, that is, electrodes 12 and 14 or 12 and 16, as the case may be.

The switch envelope 1'9 is shown in a level position so that the globule of mercury 22 makes contact only with the common electrode 12. However, it the switch ltl is now tilted about the lateral axis Y-Y extending perpendicular to the longitudinal axis XX and half way between the ends of the envelope 19, it will be seen that a contact will be established then between the electrodes 12 and 14 or 12 and 16, and this contact relation will remain so long as the switch is so tilted even though the rotation position of the switch about the longitudinal axis XX is changed.

in the aforenoted arrangement, the U-shapcd contact members 18 and 29 are shown with the open ends thereof extending about the common electrode 12 and the longitudinal axis XX so as to provide the desired operation. Heretofore, the inventors of the present device had experimented with completely circular members mounted on the inner ends of the electrodes 14 and 16 in place of the open semi-circular or U-shaped contact members 18 and Ztl. However, dificulty was encountered because it was discovered that the globule of mercury in making contact with one or the other of the circular contact members tended to collect in two or more separate droplets on either side of the circular contact member. It was then discovered that by use of the open or U-shaped contact members 18 and 2%, this difficulty was completely eliminated and successful operation of the switch may be ellected even under an extreme three hundred and sixty degrees (366) roll condition about the longitudinal axis XX.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangement of the parts, which will now appear to those skilled in the art may be made without departing from the scope of the invention. Reference is,

a therefore, to be had to the appended claims for a deiinition of the limits of the invention.

What is claimed is:

1. An electrical switch comprising a tubular envelope, said envelope being movable about a longitudinal axis and about a lateral axis, a common electrode extending into the envelope in parallel relation to the longitudinal axis thereof, a second electrode extending into the envelope in parallel relation to the longitudinal axis and in spaced relation to the common electrode, a third electrode extending into the envelope and in parallel relation to the longitudinal axis and in spaced relation to the common electrode, said second and third el ctrodes having inner ends thereof positioned within said envelope in spaced relation one to the other, a U-shaped contact member mounted at its base to the inner end of said second elec trode, and another U-shaped contact member mounted at its base to the inner end of said third electrode, said U-shaped contact members forming a mercury passage between its upper end and being positioned in spaced relation one to the other and to the lateral axis of said envelope, and a globule of mercury continuously engaging said common electrode and arranged to selectively contact said U-shaped contact members upon a tilt of the envelope about said lateral axis, and the selected U-shaped contact member retaining the globule of mercury in said selected contacting relation upon the switch envelope being tilted about the longitudinal axis thereof and releasing the globule of mercury through the passage formed between its upper ends upon said tubular envelope being tilted back about its lateral axis.

2. An electrical switch comprising a tubular envelope, said envelope being movable about a longitudinal axis and about a lateral axis, a common electrode extending into the envelope in parallel relation to the longitudinal axis thereof, a second electrode extending into the envelope in parallel relation to the longitudinal axis and in spaced relation to the common electrode, a third electrode extending into the envelope and in parallel relation to the longitudinal axis and in spaced relation to the common electrode, said second and third electrodes having inner ends thereof positioned within said envelope and encircling the inside diameter thereof, leaving a passage and arranged in spaced relation one to the other, a first contact member mounted at the inner end of said second electrode and semiencircling the inside diameter of said envelope leaving a mercury passage, and a second contact member mounted at the inner end of said third electrode, said first and second contact members being positioned in spaced relation one to the other, and a globule of mercury continuously engaging said common electrode and arranged to selectively contact said first and second contact members upon a tilt of the envelope about said lateral axis, and the first and second contact members being so shaped and arranged in relation to said common electrode as to retain the globule of mercury in said sel cted contacting relation therewith upon the switch envelope being tilted about the longitudinal axis thereof and releasing the globule of mercury through the passage upon said tubular envelope being tilted back about its transverse axis thereof.

3. An electrical switch comprising a tubular envelope, said tubular envelope being movable about a longitudinal axis and about a lateral axis extending transverse thereto and intermediate the opposite ends of said tubular envelope, a common electrode extending into the envelope through one end thereof and in parallel relation to the longitudinal axis thereof, a second electrode extending into the envelope through said one end and in parallel relation to the longitudinal axis of the envelope, and a third electrode extending into the envelope through an opposite end thereof and in parallel relation to the longitudinal axis, said second and third electrodes having inner ends thereof positioned within said envelope in spaced relation one to the other, said second and third electrodes being positioned in spaced relation to said common electrode, semi-circular contact members mounted at the inner ends of said second and third electrodes leaving a mercury passage at the ends of said contact members and positioned in spaced relation one to the other, said semi-circular contact members extending at opposite sides of the common electrode, a globule of mercury continuously engaging said common electrode and arranged to selectively contact with said semi-circular contact members upon a tilt of the envelope about said lateral axis, and the selected semi-circular contact member retaining the globule of mercury in said selected contacting relation upon the switch envelope being tilted about the longitudinal axis thereof and releasing said globule of mercury through said passage upon said tubular envelope being tilted back about its lateral axis. 7

References listed by the Examiner UNlTED STATES PATENTS 489,266 1/93 Rabbidge 200152 1,676,754 7/28 Walker 200l52 2,830,160 4/53 Engel et a1. 200-152 FOREIGN PATENTS 311,242 10/29 Great Britain.

BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCI-IAEFER, Examiner. 

1. AN ELECTRICAL SWITCH COMPRISING A TUBULAR ENVELOPE, SAID ENVELOPE BEING MOVABLE ABOUT ALONGITUDINAL AXIS AND ABOUT A LATERAL AXIS, A COMMON ELECTRODE EXTENDING INTO THE ENVELOPE IN PARALLEL RELATION TO THE LONGITUDINAL AXIS THEREOF, A SECOND ELECTRODE EXTENDING INTO THE ENVELOPE IN PARALLEL RELATION TO THE LONGITUDINAL AXIS AND IN SPACED RELATION TO THE COMMON ELECTRODE, A THIRD ELECTRODE EXTENDING INTO THE ENVELOPE AND IN PARALLEL RELATION TO THE LONGITUDINAL AXIS AND IN SPACED RELATION TO THE COMMON ELECTRODE, SAID SECOND AND THIRD ELECTRODES HAVING INNER ENDS THEREOF POSITIONED WITHIN SAID ENVELOPE IN SPACED RELATION ONE TO THE OTHER, A U-SHAPED CONTACT MEMBER MOUNTED AT ITS BASE TO THE INNER END OF SAID SECOND ELECTRODE, AND ANOTHER U-SHAPED CONTACT MEMBER MOUNTED AT ITS BASE TO THE INNER END OF SAID THIRD ELECTRODE, SAID U-SHAPED CONTACT MEMBERS FORMING A MERCURY PASSAGE BETWEEN ITS UPPER END AND BEING POSITIONED IN SPACED RELATION ONE TO THE OTHER AND TO THE LATERAL AXIS OF SAID ENVELOP, AND A GLOBULE OF MERCURY CONTINOUSLY ENGAGING SAID COMMON ELECTRODE AND ARRANGED TO SELECTIVELY CONTACT SAID U-SHAPED CONTACT MEMBERS UPON A TILT OF THE ENVELOPE ABOUT SAID LATERAL AXIS, AND THE SELECTED U-SHAPED CONTACT MEMBER RETAINING THE GLOBULE OF MERCURY IN SAID SELECTED CONTACING RELATION UPON THE SWITCH ENVELOPE BEING TILTED ABOUT THE LONGITUDINAL AXIS THEREOF AND RELEASING THE GLOBULE OF MERCURY THROUGH THE PASSAGE FORMED BETWEEN ITS UPPER ENDS UPON SAID TUBULAR ENVELOPE BEING TILTED BACK ABOUT ITS LATERAL AXIS. 